A Janesville man charged with fourth-offense intoxicated driving appeared to have overdosed on fentanyl in his car in April, according to an amended criminal complaint filed Wednesday in Rock County Court.

Janesville police say Nicholas R. Manz, 33, of 1121 Putnam Ave., drove while intoxicated at about 5:41 p.m. April 18, the complaint states. Officers found him at a gas station on Center Avenue.

Substances found in the car had positive test results for fentanyl and synthetic marijuana, according to the complaint.

Manz has other intoxicated-driving convictions in 2008 and March 12 and Dec. 1 of this year.